Blending a dirt path
Assuming you are not texture painting, I think one of the easiest ways would be to use one material for the whole thing, comprised of 2 textures (or full materials) combined together with a mask that would define the &quot;path&quot; area.
If you are looking to mix 2 PBR Materials, use 2 Principled BSDF's (one connected to each texture set), and mix them with a Mix Shader. Whatever you use for the Mix Factor will define how they are mixed. In the below example, I used a scaled down Wave Texture, with it's vectors distorted slightly by adding the influence of a Noise Texture. This gives a relatively straight path with &quot;jagged&quot; edges (shown more clearly in second image). Using it as a Mix Factor, results in a path with realistic looking edges:

You can see how the texture I made for the mix factor looks on its own, and how the light and dark areas represent the placement of the two textures. The pure white and pure black areas are the full &quot;strength&quot; of their respective textures, whereas the shades of grey represent a &quot;blend&quot; of the two, giving that fade-in look you're after (as opposed to a harsh cutoff).

If you are just looking to mix 2 single Image Textures, you can simply mix the images directly by using a MixRGB Node:

Remember these are just examples, you may have to alter some values to make it look right on your mesh (particularly in the first example). This is just to demonstrate a couple of ways different textures can be mixed.